Afghan airstrike 'killed election campaigners'

An Afghan official says 10 election campaigners were killed in an airstrike by international forces in the relatively peaceful north of the country on Thursday.

Two other people, including a candidate in the September 18 parliamentary elections, were injured in the air raid, in Rustaq district, Takhar province, provincial government spokesman Faiz Mohammad Tawhedi said.

The men were travelling in a "caravan" of vehicles when raided by "aircraft and helicopter gunships," he said.

He said the election campaigners were working for parliamentary candidate Abdul Wahed Khurasani, who had survived the bombing with injuries.

The attack came as US defence secretary Robert Gates landed in Kabul for unannounced talks.

Speaking at a joint news conference, Mr Gates and Afghan president Hamid Karzai appeared to disagree over the air strike, but the Afghan leader used milder language than in an earlier statement when he attacked the strike.

US officials, including Mr Gates, said the strike was aimed at insurgents from the Al Qaeda-linked Islamic Movement of Uzbekistan (IMU).

Mr Gates said he knew little about the incident other than that an IMU leader was targeted and killed, and that the IMU had been responsible for attacks across Afghanistan, including in Kabul.

"This is the first that I had heard that civilians may have been killed and we will certainly look into that," he said.

NATO's International Security Assistance Force (ISAF), the international counter-insurgency mission in Afghanistan, said it was "aware of the allegations" that civilians were killed.

"We're investigating to find out if it's true or not," an ISAF spokesman said.

NATO has around 150,000 troops in Afghanistan to fight a Taliban-led insurgency.

The international force has been responsible for scores of civilian deaths, many of them killed during air raids aimed against insurgents.

A recent UN report said about 20 per cent of the more than 1,300 civilians killed in the first half of the year lost their lives in NATO and other pro-government troops' actions, with most of the rest killed by militants.